Multicore optical fibers are optical fibers that include a plurality of cores embedded in a cladding matrix. The cores are typically identical or have two different types of cores placed next to each other to reduce the cross-talk between adjacent cores.
For optical communication applications like space division multiplexing, the cores have regular core arrangement or pattern, such as a triangular lattice arrangement, a square lattice arrangement, a ring arrangement or other periodic structure with select cores spacing between adjacent cores.
A regular (i.e., periodic) arrangement of the cores is necessary to facilitate coupling light into each core at the respective ends of the multicore optical fiber, as well as to reduce cross-talk. More particularly, a regular or periodic core arrangement is used to match the regular or periodic arrangement of the fibers or detector elements in connectors used at the respective ends of the multicore optical fiber to optically couple to devices of the optical communication system.